湿热盐雾大气环境印制电路板防护棚下试验研究

Experimental Study on PCB Protection in Damp and Hot Salt Fog Atmospheric Environment

目的 试验研究不同防护工艺的印制电路板在湿热盐雾大气环境下的适应性。方法 结合无防护试件,在严苛的濒海棚下环境开展4种印制电路板防护工艺的暴露试验,通过观察电路板外观,测量计算绝缘电阻、介质耐压、品质因数,以及扫描电镜、能谱分析等技术手段评价印制电路板防护工艺的性能。结果 濒海棚下环境中,无防护印制电路板腐蚀严重,电气性能显著下降。改性硅、有机硅三防漆防护的印制电路板在整个试验周期内腐蚀程度轻微,电气性能较好,表面涂层仅存在轻微起泡现象。丙烯酸三防漆防护印制电路板防护性能不稳定,印制电路板出现腐蚀现象,品质因数总体低于改性硅、有机硅三防漆防护。聚氨酯三防漆防护印制电路板在电气测试性能中表现良好,但涂层出现太多破损、起泡等缺陷,铜导线出现异常生锈现象。在介质耐压测试中,多周期呈现击穿状态。结论 在濒海区域棚下湿热盐雾环境中,涂覆有机硅、改性硅三防漆的印制电路板防护状态最好,可优先选择作为防护手段。

The work aims to study the environmental adaptability of PCB with different protection processes in a damp and hot salt fog atmospheric environment.Combined with unprotected specimens,the exposure test of PCB with four kinds of protection technology was carried out in shed environment near the sea.The performance of the protection technology of PCB was evaluated by the appearance,insulation resistance,dielectric voltage resistance,quality factor,scanning electron microscopy,energy spectrum analysis and other technical means.In the shed environment near the sea,the PCB without protective treatment was seriously corroded,and its electrical performance was also significantly reduced.The modified silicone and organosilicon PCB had mild corrosion and good electrical properties during the whole test period.The PCB protective performance of acrylic three-proofing paint protection was unstable,and the PCB was corroded.The quality factor of acrylic three-proofing paint was lower than that of modified silicon and organic silicon three-proofing paint.The electrical test performance of the PCB protected by polyurethane three-proofing paint was good,but the coating had too much damage,foaming and other defects,the copper wire had abnormal rust phenomenon,and the dielectric voltage test had a breakdown state in multiple cycles.For the PCB in the damp and hot salt fog environment in the shed environment near the sea,it is recommended that silicone and modified silicon be coated with three-proofing paint as protection means.